1. Field of the Invention
The present invention relates to a vehicle seat structure, and more particularly to a vehicle seat structure having a seat cushion and a seat back connected to a rear end of the seat cushion.
2. Description of the Related Art
Heretofore, in a vehicle seat, there have been proposed various structures for absorbing impact or shock to be applied to a seat occupant during a rear collision.
For example, JP 2003-276489A (Patent Publication 1) discloses a vehicle seat comprising a seat cushion which has a front portion fixed to a floor of a vehicle body through a bracket (front leg arm), and a rear portion adapted to be moved up and down through a link member (rear leg arm), wherein the bracket is designed to be bucklingly deformed when a rearward load is imposed on the seat cushion during a rear collision, so as to allow the entire seat to be moved rearwardly to absorb a shock to be applied to a seat occupant due to the rearward load.
JP 11-115594A (Patent Publication 2) discloses a vehicle seat comprising a seat cushion, a seat back connected to a rear end of the seat cushion, and a lifter mechanism which supports each of front and rear portions of the seat cushion relative to a vehicle body through a link member and allows a height position of the supported seat cushion to be adjusted relative to the vehicle body, wherein the seat cushion has a side frame member formed with a weakened portion adapted to cause a deformation of the side frame member when a predetermined amount or more of impact load is imposed on the side frame member, so as to absorb a shock.
In the course of researches on the vehicle seats as disclosed in Patent Publications 1 and 2, the inventers found that, when a rearward load is input from a seat occupant into a seat back during a rear collusion or the like, the input load is transmitted as a downward load to a seat cushion through a connecting member between the seat back and the seat cushion, and thereby the seat cushion is likely to be displaced downwardly to give a shock to the occupant due to a sudden change in his/her posture.